Robotic Surgical Assemblies Using Drive Screws to Reduce Cable Stretch
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Solution Overview
Problem
Cables in robotic surgical instruments stretch during use, leading to less correlated movement between the input device and the end effector, limiting the responsive performance of the robotic system.
Innovation Solution
The implementation of a surgical instrument with a drive screw and drive nut mechanism, where the drive screw is rotatably supported within a housing assembly and threadedly engaged with a drive nut, allowing for longitudinal movement upon rotation, and a drive member connected to the drive nut to translate longitudinally, reducing cable stretch by converting rotational forces into precise longitudinal movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cables are used to transmit motion from the input device to the end effector, then the system structure is simple and easy to manufacture, but cable stretch occurs during use which reduces movement correlation and responsive performance
Solution Approach 1:
The patent replaces the traditional cable-based mechanical transmission system with a robotic arm system that uses motors and control algorithms to achieve motion transmission. This substitution eliminates cable stretch issues while maintaining the ability to transmit motion from the input device to the end effector, thereby improving movement correlation and responsive performance.
2Device complexity
If cables are used for actuation, then the device complexity is reduced, but cable stretch causes lag in end effector movement reducing responsiveness
Solution Approach 1:
The patent replaces the simple cable-based mechanical system with a more complex robotic arm system incorporating motors and control mechanisms. This substitution eliminates cable stretch, thereby improving the speed and responsiveness of end effector movement, even though it increases device complexity.
3Reliability
If a robotic arm system is implemented to eliminate cable stretch, then movement correlation and responsiveness are improved, but the device complexity increases
Solution Approach 1:
The patent implements a robotic arm system that replaces the simple cable-based mechanical transmission with a motor-driven system. This substitution improves movement correlation and reliability by eliminating cable stretch, while accepting the trade-off of increased device complexity through the addition of motors and control mechanisms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enhances the responsiveness and precision of the robotic surgical instrument by minimizing cable stretch, ensuring correlated movement between the input device and the end effector, thereby improving the overall performance of the robotic system.
Implementation Method 1
Each drive assembly of the plurality of drive assemblies includes a drive screw including an elongated threaded body. The drive screw is rotatably supported within the housing assembly. The drive assembly also includes a drive nut threadedly engaged with the elongated threaded body of the drive screw such that rotation of the drive screw results in longitudinal movement of the drive nut.
Data Source
AI summary
A surgical instrument for use with and for selective connection to an instrument drive unit includes an end effector, an instrument drive connector including a plurality of drive assemblies, and a plurality of drive members in mechanical cooperation with the instrument drive connector and the end effector. Each drive assembly of the plurality of drive assemblies includes a drive screw including an elongated threaded body and a drive nut threadedly engaged with the elongated threaded body of the drive screw such that rotation of the drive screw results in longitudinal movement of the drive nut. Each drive member of the plurality of drive members includes a proximal end portion secured to a respective drive nut of one of the plurality of drive assemblies such that longitudinal translation of the respective drive nut causes longitudinal translation of the drive member to drive a function of the end effector.